for (int value=0; value<255; value++) //Increase "Power" from output ~11 to Gate in SCR flash
digitalWrite(flashPin, HIGH); // flash goes off (??)
not really seeing the point of this - why not simply put a delay after the "digitalWrite (flashPin, HIGH);" ?
Neither me, my problem was increase the signal of digital output arduino to SCR that was not strong enough to trigger the wireless trigger PT-04TM to flash, i solved the problem this way.
I don´t understand anything of arduino or electronics, my first contact with this "world" was in this project, so if anyone who understand about this want to analyse the question and turn the code better go for it!!!
if (meet == LOW){
delay(100); // delay between sound and flash
digitalWrite(flashPin, HIGH);
delayMicroseconds (20); //stretch or contract this
digitalWrite(flashPin, LOW);
delay(100); // delay between sound and flash
digitalWrite(flashPin, HIGH);
delayMicroseconds (20); //stretch or contract this
digitalWrite(flashPin, LOW);
would be my first guess.
It works, so where was the problem with the power of SCR
focalist:
I use an optocoupler with a lot of success, 2n35 I think. I'd think a SSR (Solid State Relay) would be overkill, but would work. Just remember older external flashes (and cheap new ones) sometimes dump a couple hundred volts or more across those terminals. An NPN transistor isn't enough.
I use 4N25 optoisolators in mine too, so I can keep everything separate. I've stolen the 3 pin socket off an RF-602 receiver so I can hook cameras or flash up to it. Don't fancy something going wrong and it frying a D300s.
I haven't seen too many newer cheap flashes running on high voltage though. I've tested mine with the the Yongnuo YN460-II and YN-560 flashes with no problems (dirt cheap, and as powerful as an SB-800, although only the YN-560 has the zoomable head). Also used mine with SB-600 and SB-900 flashes, as well as wirelessly through an RF-602 Tx to half a dozen flashes on receivers.
If I'm triggering flashes (as opposed to the camera), I just use the "Full Press" signal ("Half Press" happens about half a second before I actually need it to go off to ensure the camera's woken up, and ready to take a shot the instant it sees a full press signal).
I don't know about the SCR, but using the 4N25 optoisolators, I just used a 50ms delay to hold the pin high. That'll trigger a Nikon camera (assuming half-press was set in advance) or a flash (once) no problem.
I use relays (focus/shutter) for my camera and usually give them at least 100ms, but I know my Vivitar 283s will trigger from a one microsecond pulse to a MOC3020, so the inherent delay in a digitalWrite HIGH then LOW would be overkill.
My recollection of SCRs was that they latched on very short pulses, but back then, I didn't have a 'scope.